Upgrade to Angular v18

[gideonoludeyi]

Changes 🛠

What does this PR do?

• Upgrade @angular/* dependencies to v18 using the official migration guide.
• Upgrade typescript to 5.4.
• Refactor to Angular's new standalone component API using the official migration guide
• Refactor to firebase's new modular API.
• Remove the /gallery page due to conflicts between new Angular versions and unmaintained ngx-gallery dependency.
• Update SASS files to use @use directive instead of the soon-to-be deprecated @import directive.

Screenshots 🖼

Before

N/A

After

N/A

Any new npm dependencies?

NO

Testing 🧪

Changes from the latest PR are deployed to https://brockcsc-pr.web.app once the checks are complete. Can use this for testing.

Any other info needed for testing?

NO